Hi min 1982, I'm sorry you've had to find yourself on this site. Our journey began 12 months after Groenvelt68's and I gained heaps of insight reading the posts from 2011/2012.
Your mother in law's behaviour can be affected by fear, tumour position, dexamethasone....everything really. GBM is a terrible disease for all involved. As difficult as it is to accept the changed behaviour, your mother in law needs all the support and love you can give her.She may/may not be aware of her behaviour and she may/may not be able to control it.
When my husband was diagnosed in June 2012, he found it really hard to cope with the way the dexamethasone made him feel. Fortunately he was aware of this and he would try to moderate his behaviour. As his dex was reduced he rejoiced. He never managed to be off it completely before recurrence 5 months later, and when the dose was increased, he felt he was able to control himself since he knew what to expect.
Not everyone is able to do this so family and friends need huge amounts of patience and tolerance.
My husband survived for 13 months despite treatment which included surgery x2, gliadel wafers, radiotherapy, temozolomide, antiepileptic drugs, and Avastin. He was also involved in a clinical trial.
I wish you and your family all the very best.
